new GM 4.3L V-6

[WishIhadatruck]

Originally Posted By: A_Harman
Originally Posted By: supton
Looks like the 200 and 229 were odd fire, while the 4.3 was always even. Wikipedia Link

I forget, do 60 degree V6's need balance shafts?

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This new V6 is quite a step ahead, but it seems still a step behind. 285hp? Seems like everyone else is running 300+hp, and in the end, hp gets the work done.

Now if it had a proper transmission you could lug the motor a bit and let its torque run free...


The 200 and 229 V6's were odd fire, but they did have split crankpins. On those engines, the pins were split 18 degrees instead of the 30 degrees required to make a 90 degree V6 even-firing.

Yes, 60 degree V6's need balance shafts to eliminate free moments caused by piston accelerations. Any V-type engine with an odd number of cylinders on a bank will have free moments.

The new 4.3 V6 basically replaces the 4.8L V8. Comparing the power and torque figures:
4.3 V6 makes 285 HP @ 5300 rpm, and 305 ft*lbs @ 3900 rpm
4.8 V8 makes 285 HP @ 5400 rpm, and 295 ft*lbs @ 4300 rpm

And comparing to the 3.6 V6:
288 HP @ 6300 rpm, 270 ft*lbs @ 3400 rpm in the Traverse, which is the heaviest vehicle that GM puts the 3.6 in. Yes, it makes more power in cars and small SUV's. But 278 ft*lbs of torque is as much as it makes in any vehicle, and that's at 4800 rpm in the Camaro.


Not only that, but if you compare the power curves of the new 4.3L to even the most powerful 3.6L, the 3.6L is only making more HP at over 5,000 5,500 rpm, I don't remember exactly. The 4.3L is far more powerful in the rpm's I'd normally be using. Seems like a pretty nice motor.

 

[userfriendly]

If they mini-me the 6.2 it comes out about 283 cid.
Now where have I seen that number before?

It also makes sense from a logistics point of view.
All that is needed is matching V6 heads.

Anytime I see a Michigan address, I wonder who
or what he knows, and is not telling.

Come on, give us the goods.

 

[punisher]

Old rule of thumb: If the engine was designed to be used with computer engine controls, it is an even fire (split journals). Odd fire engines/solid journals use carbs and maybe electronic distributors.

Something to do with the old GM CCC systems not being able to properly figure/time ignition/fuel injection timing without an even number of degrees between events. I know the old GM 3.8s with a carb/HEI were odd fire (funky looking reluctor), and later EFI models were even fire (like the 3.8 Turbos).

 

[ls1mike]

Not sure I understand as you can run a carb on any LS motor, plenty of folks do.
I am probably just misunderstanding.

 

[userfriendly]

I'm sure intake manifolds will be available soon for the new 4.3 V6
so carburetors can be installed on it.

One way around the odd/even firing order would be to install a crank trigger.

A crank position sensor by any other name.

Last spring I looked at the new little Cadillac, opened the hood and thought
to myself "no-way".

Now if they put a mini-me 6.2 in that car, GM are you listening?

A 283 cid V6.....

Naw, forget the Caddy, start from scratch with a Buick on the same platform.

We haven't had a proper Buick for a long time.

 

[TiredTrucker]

Originally Posted By: A_Harman
But the new 4.3 has cylinder deactivation. It deactivates two cylinders, leading to a V4 mode with uneven firing intervals:
bang-bang-skip-bang-bang-skip


My 5.3L had the cylinder deactivation... until the second day I owned it. At 240 miles on the odometer, that feature got disabled. I didn't want it, I didn't order it, and after reading lot of TSB's over issues with it, I decided to deactivate that feature right out of the gate. Just me I guess. In the military, I expected everyone to do their part. I expect the same from an engine. No cylinders going out on union/gooberment sponsored smoke breaks while the others work. I paid for 8 cylinders, and I expect them all to work, all the time, every time.

 

[hattaresguy]

They do work, AFM is a great system.

A new 6.2 truck will do just as good if not better than my old 4.3, while making over twice the HP and about twice the torque.

 

[userfriendly]

Is the Mercury Marine engine this 4.3 V6 or the old SBC type?

What would their torque and hp numbers be?

Also if Mercury is using this engine, would they be the first to
turbo it, if its up to the task????